Table 2. Effect of covariates on estimated fetal weight at 30 and 40 weeks of gestation.

The top panel shows the Estimated Fetal Weight (EFW) centiles at 30 weeks (left) and 40 weeks of gestation (right) for a female fetus of a nulliparous African American mother, having a height of 163 cm, weighing 64 kg at first visit, non-smoking, and without diabetes. The middle and bottom panels display the effect of non-pathologic and pathologic covariates, respectively. Effects are expressed as a percentage change in weight. Positive values correspond to an increase while negative values to a decrease in EFW centiles. Values in bold represent significant effects (p<0.05). For e.g. the effect of fetal sex (male vs female) is associated with about 2% increase in EFW, and this effect is the same at 30 weeks and 40 weeks gestation, and affects all centiles similarly. By contrast, maternal height has a stronger positive effect at higher EFW centiles, and this effect does not depend on gestation. The positive effect of 10 additional kg in maternal weight (with normal BMI range) is about twice as large at 40 weeks as is at 30 weeks, for all centiles.

		EFW (g) at 30 weeks*					EFW (g) at 40 weeks*
	5th	10th	50th	90th	95th	5th	10th	50th	90th	95th
	1206	1260	1440	1643	1716	2777	2914	3369	3773	3902
Effect (% change)
Fetal Sex (Male)	2.3	2	1.9	1.9	2.4	2.3	2	1.9	1.9	2.4
Maternal height (10cm)	0.9	1.0	1.2	1.8	1.9	0.9	1.0	1.2	1.8	1.9
Maternal weight (10kg)	0.6	0.7	0.6	0.6	0.6	1.4	1.4	1.1	1.2	1.1
Para 1	0.1	0.8	0.5	1.1	0	1.1	2.1	0.7	2.4	0.7
Para 2	1.4	1.9	1.2	2.4	1.4	3.4	3.4	2.2	4.1	3.0
Para 3	1.0	0.9	1.5	2.3	1.8	1.1	0.2	2.4	4.0	3.7
BMI<20.5	1.6	0.8	−1.4	−2.0	−2.2	1.6	0.8	−1.4	−2.0	−2.2
BMI>40.4	−1.4	−1.3	−0.9	−0.2	1.0	−5.3	−4.6	−3.3	−1.7	0.2
Smoking (Yes)	−3.6	−2.8	−2.1	−2.5	−2.5	−7.8	−5.5	−3.2	−3.5	−2.4
Diabetes	5.4	4.6	3.4	3.7	3.1	6.5	5.6	4.2	4.6	4.5
Preterm Delivery	−12.0	−9.8	−2.8	0.3	1.3	−14.5	−11.9	−3.5	−0.7	1.3
Fetal anomalies	−5.1	−3.7	−2	−0.8	0.8	−5.1	−3.7	−2	−0.8	0.8